The PSNI are questioning two men over a pipe bomb attack on a house in Carrickfergus which has been linked to an ongoing feud between rival loyalist terrorists.
No one was injured in the attack but minor damage was caused to the property on Cairnhill Walk last night.
Police were also sent in large numbers to the town's Marine Highway area, where large crowds of loyalists had gathered.
Tensions have grown since the outlawed Ulster Defence Association expelled members of its South East Antrim unit, accusing them of being drug dealers and criminals.
In July a police officer was shot and wounded after rival loyalist gangs clashed in Carrickfergus's Castlemara estate. And a month later fights broke out between mainstream UDA and South East Antrim UDA prisoners inside Northern Ireland's Maghaberry Jail.
Following last night's trouble, a spokeswoman confirmed: "Police are investigating the possibility that these incidents may be connected to ongoing tensions within the loyalist community in South East Antrim."
The British government warned in August that funding for loyalist communities would be withdrawn if the Ulster Defence Association (UDA) does not decommission weapon.